In the summer of 2022, the intricate quarantine policy in China compelled me to forgo the plans to return home. Departing from the East Coast of the United States, where I resided, I headed to San Francisco—the closest point on the other side of the Pacific from my homeland, tracing a potential sense of belonging. The essayistic film Coast to Coast (Preamble) oscillates between personal encounters, remnants of the past, and several proxies, examining the ambiguous temporality on the coast and my own condition of being inbetween during that period. It is the prelude of a long-term project Coast to Coast, which will be divided into several chapters to address subjects, including the oceanic epistemology from ancestors, the image(ry) of the vessel, and the historical legacy of optical navigational devices along the Chinese coast.